This invention relates generally to a method of manufacturing ball bearing retainers and more particularly to a method of manufacturing ball bearing retainers from narrow strip material.
Prior art ball bearing retainers have been manufactured from wide flat strips of material. First, a ring is sheared from the wide flat strip. Ball pockets are then pressed into the strip to retain the balls at desired intervals. Two rings are used, one on each side. The rings are welded or otherwise locked together. Shearing the retainer from a wide flat strip results in excessive waste material. One common retainer, for example, wastes 71% of the material purchased. Scrap is no longer a salable commodity. The manufacturer must pay to have the scrap disposed of.
In rolled steel, there is a grain or directional quality to the strips. This is a result of discontinuities being elongated along the direction of rolling. In a retainer of the prior art methods, the grain direction will vary. Where the grain is not aligned with the peripheral edges of the retainer, failure of the retainer can occur.
Various methods have been tried to eliminate the waste resulting from shearing the retainer from a wide flat strip. One method forms the retainer from a narrow strip of material. The strip is curved into a ring of approximate finished diameter and the ends are welded together. The ball pockets are then simultaneously pressed into the ring. This method causes excessive thinning of the retainer in the area of the ball pockets which can lead to premature bearing failure, especially in high speed applications.
The foregoing illustrates limitations known to exist in present ball bearing retainer manufacturing methods. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.